#include <iostream>
#include <string>

using namespace std;
 
inline void test(const char* title, bool value)
{
	cout << title << " returns " << (value ? "true" : "false") << endl;
}

int main()
{
	string s1 = "DEF";
	cout << "s1 is " << s1 << endl;
	string s2;
	cout << "Please enter s2: ";
	cin >> s2;
	cout << "length of s2: " << s2.length() << endl;

	test("s1<=\"ABC\"", s1 <= "ABC");
	test("\"DEF\"<=s1", "DEF"<=s1);
	s2 += s1;
	cout << "s2 = s1 + s2: " << s2 << endl;
	cout << "length of s2: " << s2.length() << endl;
	
	return 0;
}